Percentage Of Na Research Articles

High-NaCl diets increase natriuretic and diuretic responses in salt-resistant but not salt-sensitive SHR

This study tested the hypothesis that NaCl-sensitive spontaneously hypertensive rats (SHR-S) display a defect in natriuretic and diuretic responses to acute volume loading that contributes to the rise in arterial pressure observed when the rats are fed a high-NaCl diet. Seven-week-old SHR-S and NaCl-resistant SHR rats (SHR-R) and normotensive (Wistar-Kyoto and Sprague-Dawley rats) were fed high- or basal NaCl diets. After 2.5 wk on the diets, preinstrumented conscious rats received an intravenous infusion (5% body wt; 0.5 ml/min) of isotonic saline, and urine was collected through a bladder catheter for 90 min. Control rats on the high-NaCl diet (compared with basal) excreted a significantly greater percentage of Na+ and volume load. In contrast, SHR-S on high-NaCl diet (compared with basal) had a very small increase in natriuretic response and no increase in diuretic response to volume expansion. The effect of renal denervation on natriuretic and diuretic responses to volume load was tested. In SHR-R on 1 and 8% NaCl diets, renal denervation had little or no effect on these responses, suggesting that renal nerves do not play a prominent role in the dietary NaCl-induced increases in the natriuretic and diuretic responses to volume load. These results demonstrate that NaCl-resistant rats rapidly adapt to diets high in NaCl content with increased natriuretic and diuretic responses to acute volume loading. The failure of SHR-S to adapt to the dietary challenge may result in volume loading and a secondary increase in arterial pressure after feeding.

Formation and hydrolysis of acetals catalysed by acid Faujasites

Dimethyl and cyclic ethylene acetals can be obtained in the presence of HY zeolites by treatment of the corresponding carbonyl compound with trimethyl orthoformate at room temperature or with ethylene glycol using a Dean-Stark system, respectively. The relationship between the percentage of Na + exchange of the zeolite and the initial reaction rates shows that only strong acid sites are active in the dimethyl acetal formation. Similarly, regeneration of the parent carbonyl compound was accomplished by simply heating suspensions of the appropriate acetal in carbon tetrachloride with HY catalysts. Evidence supporting the implication in the hydrolysis of the adsorbed water remaining on the zeolite after thermal activation was drawn from the results obtained using a dried solvent and a highly dealuminated zeolite. The possibility of using hydrolytic cleavage of acetals as a chemical activation procedure for zeolites was tested.

X-ray microanalysis of the fingernails in cirrhotic patients.

The element content of clipped nails of 13 patients with liver cirrhosis was examined by X-ray microanalysis, and compared with that of 50 healthy subjects. The results showed a statistically significant increase in the percentage of Na, Mg and P and a slight, but statistically significant decrease in S and Cl. The percentage of K, Ca, Fe, Cu and Zn did not show any difference from that of the controls. The findings indicate that X-ray microanalysis may be a valuable tool for the simultaneous examination of a large number of elements in the fingernails.

Effects of phenytoin on primary glial cell cultures.

The activity of enzymes involved in anion and cation transport, the concentration of intracellular potassium (K+i), and the transmembrane potential (Em) were determined following acute and chronic exposure of primary astroglial cultures to micromolar concentrations of phenytoin (PHT). Na+, K+-ATPase activity of homogenates of cultured glial cells was determined in the presence of an increasing K+ concentration (1-20 mM). Acutely, PHT had little effect on the K+ activation pattern of Na+, K+-ATPase. In contrast, the percentage of Na+, K+-ATPase activated by elevating the K+ concentration was dose dependently increased by chronic PHT treatment. This effect was accompanied by a marked increase in K+i and a significant membrane hyperpolarization. The acute effect of PHT on the Em was biphasic, characterized by membrane hyperpolarization at concentrations of 10(-6)-10(-5) M; at concentrations between 10(-5) and 10(-4) M, the Em progressively returned to control values. These results suggest that glial cells acutely and chronically treated with therapeutic concentrations of PHT have an enhanced capacity to control elevated extracellular potassium levels. Return of the Em to control values at PHT concentrations greater than 10(-5) M suggests that these cells are less able to regulate extracellular potassium. These data can partially explain the excitatory effects of PHT at high therapeutic concentrations.

Relationship between direct-potentiometric and flame-photometric measurement of sodium in blood.

The relationship between direct-potentiometric and flame-photometric measurements of sodium has been studied in human sera and other, simpler systems. When water content was varied by using an inert substance (silica), de-ionized sera, or de-ionized individual proteins, the percentage that the flame photometric values were of the direct potentiometric Na+ values was identical to the measured water content. However, in 35 patients the percentage of Na+ values was 99.1% and the water content was 92.0%, a discrepancy of 7.1%. De-ionization of sera removed this discrepancy, apparently because of the lower pH of the de-ionized sera. The percentage of flame-photometric to direct-potentiometric Na+ values varied as a function of pH in pooled sera; in lyophilized and reconstituted sera; and in de-ionized, lyophilized, and reconstituted sera. Four explanations for the discrepancy between the percentage of Na+ values and the water content are discussed: a calibration problem, a measurement artifact, Na+ binding, and water binding. At this time there are no definitive data concerning which explanation is correct. We expect that our finding of a pH dependency for the percentage of measured Na+ values can be used to develop model systems to elucidate the mechanism producing the discrepancy between the percentage of Na+ values and the water content.

Spectroscopic study of surface properties of various NH4-exchanged X zeolites

The nature of hydroxyl groups formed during deammoniation of three NH4-X zeolites has been investigated in terms of their stability during dehydroxylation and their acidity towards bases like pyridine. It appears that besides the two principal bands at 3660 and 3560 cm–1 always observed in spectra of decationated X and Y zeolites, a third band is present at 3625 cm–1, the intensity of which depends on the percentage of Na+ ions exchanged and, for a given sample, on the outgassing temperature. This band is attributed to hydroxyl groups which show acidic properties, are very accessible to large molecules, and are therefore probably located inside the large cavities of the network, but which are very sensitive to dehyroxylation at relatively low outgassing temperatures.

Microvariations in Edaphic Factors and Species Distribution in a Mediterranean Salt Desert

Microvariations of some edaphic factors were correlated with the occurrence of common halophilous plants in the Mallahet Mariut Depression (Burg El-Arab, Egypt). Soil profiles were sampled at 43 sites and the samples tested for pH, and percentage of Na+, K+, Ca++, Mg++, Cl-, SO4--, CaCO3, organic matter, and particle size. Vegetation was sampled in each stand by the point-centered quarter method, whereby relative density and frequency were evaluated for each species. These were summed to give an importance value. Horizontal and vertical variations were highly significant for almost all soil characters. These variations were attributed to variations in topography, composition of the bedrock, amounts and quality of wind-borne material and the nature of dominating species. Multiple correlations between the phyto-sociological behaviour of species and microvariations in soil characters were higher than simple ones. Vegetational variations may be controlled by a multitude of interacting factors. The analysis of correlation indicated that the role of individual ions and their combinations may be more important than that of other factors.

Changes in mineral composition of eggshells from black ducks and mallards fed DDE in the diet.

Diets containing 10 and 30 ppm (dry weight) DDE were fed to black ducks, and diets containing 1, 5, and 10 ppm (dry weight) DDE were fed to mallards. Among the results were the following changes in black duck eggshell composition: (a) significant increase in the percentage of Mg, (b) significant decreases in Ba and Sr, (c) increases (which approached significance) in average percentage of eggshell Na and Cu, (d) a decrease in shell Ca which approached significance, (e) patterns of mineral correlations which in some instances were distinct to dosage groups, and (f) inverse correlations in the control group between eggshell thickness Mg and Na. Changes in mallard eggshells were: (a) significant increase in percentage of magnesium at 5 and 10 ppm DDE, (b) significant decrease in Al at 5 and 10 ppm DDE, (c) a significant decrease in Ca from eggshells from the 10 ppm DDE group, and (d) an increase in average percentage of Na in eggshells from DDE dosed ducks which approached significance.